The work described in this paper considers 3D CFD (computational fluid dynamics) simulations of an adiabatic stratified liquid-vapor flow at the inlet of a compact plate heat exchanger using the commercial CFD code "FLUENT" and an in-house code "NEPTUNE 3D" developed by CEA and EDF. An experimental loop is built up that represents a compact plate heat exchanger in which the liquid and vapor flow rates in the different channels are measured and the flow inside the cylindrical distributor of diameter greater than that of the inlet tube can be visualized. The numerical predictions showed the good agreement with the experimental measurements. The interfacial shear stress was calculated in a steady stratified flow and compared with the computed shear stresses by the two codes.

The aim of this study is to investigate the flow pattern behaviour by using computational fluid dynamic (CFD) approach. The square profile was chosen in purpose to have a better understanding of the behaviour which is relevant to the engineering applications. Numerical simulation was performed on various turbulence models with the range of Reynolds number from 6000 to 80000 with three incidence angles of 0°, 15°, and 30°. Mesh dependency study was performed with coarse, base and fine meshes. Fine mesh and standard k-ω were chosen as the best meshing and turbulence model to perform the simulation due to the capability in terms of less absolute error on aerodynamic coefficient and clear flow visualisation capture. It was found that the average values of Strouhal number for square profile was 0.12. For this particular study, the changes of incidence angle and variation of Reynolds number gave a significant flow pattern behind a square profile. The size of the vortices became smaller and closer to the structure as the incidence angle increased. At high Reynolds number, it was also observed that the size of the vortices increased progressively. The prediction of flow pattern behind square cylinder was successfully determined by using CFD approach.